KETOMETHYLENE AND METHYLENEAMINO PSEUDOPEPTIDE ANALOGS OF INSECT ALLATOSTATINS INHIBIT JUVENILE-HORMONE AND VITELLOGENIN PRODUCTION IN THE COCKROACH BLATTELLA-GERMANICA
Md. Piulachs et al., KETOMETHYLENE AND METHYLENEAMINO PSEUDOPEPTIDE ANALOGS OF INSECT ALLATOSTATINS INHIBIT JUVENILE-HORMONE AND VITELLOGENIN PRODUCTION IN THE COCKROACH BLATTELLA-GERMANICA, Insect biochemistry and molecular biology, 27(10), 1997, pp. 851-858
Metabolic studies on insect allatostatins have suggested that the dipe
ptide Leu-Tyr may be a target for endopeptidases. In order to increase
resistance to degradation, methyleneamino Psi[CH2NH] and ketomethylen
e Psi[COCH2] peptide bond surrogates have been introduced at the posit
ion Leu(3)-Tyr(4) of the allatostatin Asp-Arg-Leu-Tyr-Ser-Phe-Gly-Leu-
amide (BLAST-2), and Leu(3)-Phe(4) of [Phe(4)]BLAST-2, respectively. A
ssays of inhibition of juvenile hormone (JH) synthesis in vitro by cor
pora allata from the cockroach Blattella germanica showed that both an
alogues were similarly active to the respective model peptides. The me
thyleneamino analogue was further tested in vivo as an inhibitor of JH
synthesis, and in vivo and in vitro as an inhibitor of vitellogenin p
roduction by the fat body of B. germanica. The analogue was less activ
e than BLAST-2 when tested in vitro, but more active than it when test
ed in vivo. (C) 1997 Elsevier Science Ltd. All rights reserved.